The present invention relates to a process and device for inflating a tire. The invention applies to the inflation of a tire, the beads of which are respectively intended to be mounted on peripheral seats of a special rim, this inflation being effected without using the valve of said rim.
The structure of this rim is described in detail in U.S. Pat. No. 5,836,366.
As can be seen in FIG. 1, to which reference will be made hereafter, said rim 10 comprises, starting from its peripheral edges formed of two projections 11 and 12, a first and a second seat 13 and 14 inclined towards the outside and intended respectively to receive a first and a second bead 21 and 22 of the tire 20. Between the seats 13 and 14 there is provided, firstly, a bearing surface 15 intended to receive a bearing support 23 for the tread 24 and, secondly, a mounting groove 16 connecting the bearing surface 15 to an axially inner flange 17 of said first seat 13.
In the Test of the present description, by convention the seat which is adjacent to the groove 16 will be referred to as the first seat 13, and the seat which is on the opposite side from said groove 16 will be referred to as the second seat 14.
As for the axially outer flange of each seat 13, 14, it is formed by the corresponding peripheral projection 11, 12.
In known manner, the tire 20 is mounted on this special rim 10 in the following manner.
The first bead 21 is presented on the rim 10, on the side of the second seat 14, then this first bead 21 is slid axially over the bearing surface 15 so as to introduce it into the groove 16. Then the second bead 22 is mounted on the second seat 14.
Then, in an extraction step, the first bead 21 is extracted from the groove 16 so as to bring it axially against the outside of the projection 11 of the first seat 13.
Finally, in a mounting stage, this first bead 21 is mounted on the first seat 13.
Among the devices for inflating without using a valve which are known to date, mention may be made in particular of the device described in German Patent Specification DE-A-3 411 433, which comprises a bell formed of a cover of an upturned U-shaped cross-section. This bell is intended to be mounted hermetically in one of the sidewalls of a tire which has beforehand been mounted on the seats of a rim and which lies with its other sidewall flat on a horizontal support, also hermetically.
This rim comprises said seats on its inner face, and these seats are connected together by a planar central portion which is extended by two kinked sections directed towards the inside of the rim. Each seat is axially delimited, on the inner face of the rim, by one of said kinked sections and by a peripheral projection which forms an axial end of the rim and which is also directed towards the inside thereof, such that these seats are symmetrical to each other relative to said central portion.
When the tire is wedged between said support and said bell, the beads of the tire are thus mounted on said seats.
The bell is provided, within its internal space and close to its side wall, with four sliding means which may possibly also be pivoting means, such as levers, which are provided to bear on the upper bead located opposite the bell, so as to bring it towards the lower bead and thus to form an annular space between this upper bead and the rim, around the entire periphery of said bead.
Following the formation of this space, the tire is inflated by injecting compressed air into the bell and, consequently, between the tire and the rim via said space. Then said bearing means are caused to slide in the opposite direction, the effect of which is to reposition said upper bead on the corresponding seat, and the injection of compressed air into the bell is terminated, such that the tire is in the inflated state.
Mention may also be made, among the valve-less mounting devices, of those described in German Patent Specification DE-A-3 423 307 and in Belgian Patent Specification BE-A-888 537, which differ essentially from the former in that the bearing means which each of them comprises are formed by the cylindrical side wall itself of the corresponding bell, which is provided to be able to slide axially, that is to say, parallel to the axis of revolution of the tire.
One major disadvantage of these known inflation devices is that they are not suitable for inflating a tire mounted on a rim, such as the special rim described in the aforementioned U.S. Pat. No. 5,836,366, because, once said first bead of the tire has been mounted on said first seat of this special rim, the axially inner flange of this first seat and the aforementioned inclination of the latter towards the outside would hinder the circumferential deformation of this first bead towards said second bead, for creating said annular space.